realtek: 6.6: copy patch 311-add-i2c-mux-rtl9300-support

Copy the patch file to 6.6. No further processing required as
it applies cleanly to the new kernel

Signed-off-by: Markus Stockhausen <[email protected]>

target/linux/realtek/patches-6.6/311-add-i2c-mux-rtl9300-support.patch

@@ -0,0 +1,46 @@
+From f4bdb7fdccdfe3fa382abe77f72a16c2f2e6add0 Mon Sep 17 00:00:00 2001
+From: Birger Koblitz <[email protected]>
+Date: Sat, 11 Dec 2021 20:25:37 +0100
+Subject: [PATCH] realtek: Add support for RTL9300/RTL9310 I2C multiplexing
+
+The RTL9300/RTL9310 I2C controllers have support for 2 independent I2C
+masters, each with a fixed SCL pin, that cannot be changed. Each of these
+masters can use 8 (RTL9300) or 16 (RTL9310) different pins for SDA.
+This multiplexer directly controls the two masters and their shared
+IO configuration registers to allow multiplexing between any of these
+busses. The two masters cannot be used in parallel as the multiplex
+is protected by a standard multiplex lock.
+
+Submitted-by: Birger Koblitz <[email protected]>
+---
+ drivers/i2c/muxes/Kconfig                     |  9 +++++++
+ drivers/i2c/muxes/Makefile                    |  1 +
+ 2 files changed, 10 insertions(+)
+
+--- a/drivers/i2c/muxes/Kconfig
++++ b/drivers/i2c/muxes/Kconfig
+@@ -99,6 +99,15 @@ config I2C_MUX_REG
+ 	  This driver can also be built as a module.  If so, the module
+ 	  will be called i2c-mux-reg.
+ 
++config I2C_MUX_RTL9300
++	tristate "RTL9300 based I2C multiplexer"
++	help
++	  If you say yes to this option, support will be included for a
++	  RTL9300 based I2C multiplexer.
++
++	  This driver can also be built as a module.  If so, the module
++	  will be called i2c-mux-reg.
++
+ config I2C_DEMUX_PINCTRL
+ 	tristate "pinctrl-based I2C demultiplexer"
+ 	depends on PINCTRL && OF
+--- a/drivers/i2c/muxes/Makefile
++++ b/drivers/i2c/muxes/Makefile
+@@ -14,5 +14,6 @@ obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux
+ obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o
+ obj-$(CONFIG_I2C_MUX_PINCTRL)	+= i2c-mux-pinctrl.o
+ obj-$(CONFIG_I2C_MUX_REG)	+= i2c-mux-reg.o
++obj-$(CONFIG_I2C_MUX_RTL9300)	+= i2c-mux-rtl9300.o
+ 
+ ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG